Mechanism for converting rotary into oscillatory motion



Apr. 17, I923.

R. GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INTO OSCILLATORY MOTION Filed y 2'7 1921 3 Sheets-Sheet l Apr. 17, 1923. mszms R. GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INTO OSCILLATORY MOTION Filed y 2'7 1921 5 Sheets-Sheet 2 Apr. 17, 1923. l,452,@38

v R; GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INTO OSCILLATORY MOTION Filed May 27 1921 1 3 Sheets-Sheet 3 yam mime; IRMA/W4 W6 v I MM Patented A r. 17, 1923. Ldfififidti TE Ed @ii i ltiifi.

RUDOLF GOLDSCHMID T, OF BERLIN, GERMANY, ASSIGNOR TO DET TEKNISKE FORSQGSAKTIESELSKAB, OF ORIDBUP, CHARLOTTENLUND, DENIVIAZRK, A

COMPANY or DENMARK.

MECHANISM non eonvne'rrne ROTARY rnro OSGILLATDRY MOTION.

' Application filed May 27, 1921 Serial No. 473,033.

T all whom it may concern. force corresponds with an equal reaction P 55 Be it known that I, RUnoLF GoLnsoI-rMIDT, which is set up in the crank bearing K. The

a German citizen, residing at 45 Linden forces P are in turn absorbed by the ma- Allee, West End, Berlin, Germany, have chine frame.

invented new and useful Improvements in Referring now to Fig. 2, the apparatus is Mechanism for Converting Rotary into Osso arranged that the crank bearing K is not 50 cillatory Motion, of which the following is fixed to the frame, but is connected with a aspecification. slide block V which can also reciprocate The present invention relates to the probetween the guides C so that the periodic duction of oscillatory'motion from rotary reacting forces P cause the slide block V motion and has for its object to utilize the to oscillate in a similar manner to the oscil- 65 forces set up during the acceleration and lation of the crosshead IV. If the masses retardation of the masses. of the two sliding bodies V and WV are repl In order that the invention may be more resented respectively by M and M the path l clearly understood, reference is hereinafter of reciprocation of the two bodies will be made to the accompanying drawings wherein inverse proportion to the masses. Move- 70 on ment is dependent on the well-known phys- F igrl is a side view of a known arrangeical law that the centre of gravity remains ment. stationary. If S be assumed to be the com- Fig. 2 illustrates a modification thereof mon centre of gravity of the two bodies V according to the present invention. and W at distances represented by a, Z) re- 75 Fig. 3 is a partial side view and Fig. 4 spectively therefrom, then at any moment, a plan of a modified arrangement. M Kazh i Xb.

Fig. 5 is a detail view of a modification. As the slide block V may be connected to Fig. 6 is a sectional View of one form of any reciprocatory element, such as a hack the present invention employing excentrlcs. saw whereby the reacting forces act upon the Fig. 7 is a view ofthe same in sectlon o freely movable crank bearing, the driving the line 12 of Fig. 6. means may be aptly termed a reaction driv- Fig. 8 illustrates a further form of the ing gear. 30 invention. The direction of the travel of the belt at Figs. 9, 10 and 11 show three different ar right angles to the path of reciprocation is rangements for determining the path of reintentionally selected in order that, if the ciprocation. belt is sufficiently long, the sliding move- Figs. 12 and 13 are curves or graphical ment shall be affected as little as possible. 35 representations hereinafter referred to. It will be understood that instead of using F ig. 14: illustrates a modification of the a belt drive, any other suitable driving 90 arrangement shown in Fig. 8. mechanism may be employed which will not Fig. 15 is a side'view (partly in section) interfere with the oscillation, as for examillustrating the invention applied to a pile ple, a square shaft, flexible shaft or Cardan 40 driver or other impact tool. shaft.

Referring to Fig.1 of the drawingsm hich Figs. 3 and 4 illustrate a modification of 95 represents a common arrangement for conthe arrangement shown in 2 in which verting rotary into reoiprocatory motion, the crosshead IV driven by means of two K represents a. crank hearing, A a crank cranks A and A and their connecting rods and B a connecting rod. The crank A is B and B shafts L and gearing N being driven from the motor D by means of belt provided in order that the two cranks A 100 pulleys G. H. and a belt F. In this hypoand A may rotate at the same angular thetical illustration, it is assumed that the velocity in opposite directions. In this manapparatus is not performing work, but ner the lateral stresses set up on the guides merely eflecting the free reciprocation of a C by the crosshead IV are counter-balanced.

crosshead vV sliding between the guides C. It is then possible to dispense with the If the crosshead W is of considerable weight, guides C for the crosshead W.

a substantial force P will be necessary for In Figs. 3 and 4 the cranks A and A are l its acceleration and retardation. This also equal in length to the connecting rods B and B and the apparatus is so arranged that the crosshead IV can travel past or between the slide blocks V. The sphere of action is thus equal to four times the length of the crank instead of being twice the length of the crank in cases where the connecting rod is longer than the crank.

Fig. 5 is a diagrammat-ical illustration showing how the mass of the crosshead IV may alternatively be integral with the connecting rods B and B The construction of the connection between the crosshead IV or its equivalent and the slide block V may be of any preferred type such as link mechanism, excentrics, parallel or elliptical link motion, lazy tongs or the like.

Figs. 6, 7 and 8 illustrate practical constructions thereof.

In Figs. 6 and 7 the crank and connecting red are replaced by excentrics thereby forming a compact and strong construction. The

slide block V is formed with a yoke and crosspin R upon which the excentrics A A and A are rotatably mounted within excentrics B B and B respectively. The excentrics A A and A replace the cranks hereinbefore referred to whilst the excentrics 13 B and B replace the connecting rods. In the appended claims I wish it to be understood therefore that the term crank mechanism is intended also to include an arrangement of excentrics such as herein illustrated. The mass of the reciprocating weight W is in this case mounted upon the excentrics B B and 13 but is supple- 'mented also by the weight of the excentrics A A A and B 13 and B The excentries A and A are rotated in the same direction while the excentrie A is rotated in the opposite direction thereto by means of bevel pinions S and S and a driven shaft 0 which is of square section to slide within the driving member. The displacement of the mass in this case is equal to twice the sum of the radius of excentricity of the excentrics A and B Fig. 8 shows an arrangement for the di placement of the reciprocating mass IV by means of planet gearing. The sun wheel S is fixed upon the slide block V and the planet wheel S is carried-by a crank A. The outer planet wheel S is likewise rotatably carried on the crank A and is fixed. to the connecting rod B which carries the reciprocating weight IV. The radii of the sunwheel S and planet wheel S may be assumed to be in the proportion of 2 to 1. The weight W will then reciprocate in a horizontal path. In this case the rotation of the crank A is etl'ected from the motor I) through the medium of-a flexible shaft 0.

As hereinbefore described, the movement of the body V relative to the body W is de termined, but there is no fixed conjoint location and amplitude of the oscillations or continuous displacement of the centre of oscillation.

In order to obtain oscillation abouta fixed point, the body V may be located between two springs U and U as in Fig. 9, these springs being alternatively compressed during the reciprocatory movement. tively a single spring adapted both for compression and extension maybe adopted or, as illustrated in Fig. 10, the body V may strike against buffers U and U Instead of employing spiral springs as illustrated in the drawings, it will be understood that any form of resilient means may be employed such as blade springs or the like. \Vhen the oscillation takes place continuously over a predetermined path, the centre of oscillation remaining constant. the reaction driving gear substantially replaces the crank. It has, however, the advantage that at any moment the accelerating and retarding forces of the bodies V and IV counter-balance each other, apart from the useful work done, so that the system is completely balanced. There may be cases in which no frame is provided in proximity to the reciprocating body in which case the body will have no fixed guide as in the case of guide C in Fig. 2. In such case the body Vinust rebound against the body W.

Such a case may occur, for example, if a mechanism such as that shown in Fig; 8 is mounted at the free end of the wing of a vibrating wing flying machine in which'the wing is mounted to' oscillate about a fixed point 011 the frame of the machine so that the body IV reciprocates'in a vertical or inclined path. The crank A mounted at the end of the wing may then be driven by means of a shaft mounted in the wing and extending outwardly therefrom.

The advantages of the mechanism become especially apparent if the specific qualities are to be utilized which arise from the transformation from mechanism according to Fig. 1 into a reaction driving Alternaplacement of the bulfers in one direction or the other,the location of the centre of. oscillationwill be varied. This control may be effected with very little expenditure of energy as the displacement of the buffers may be effected whilst the bodyV is underway or in a position intermediate the'bulfers. V The operation and workingposition of a reciprocating element such as a hack-saw reoiprocated by the body V, can thus be varied to a considerable extent whilst the mechanism isin operation and without cessation of work.

Complete utilization of the free location of the path of oscillation can be attained if the periodic forces acting onthe reciproeating body V are used in conjunction with a force acting in one direction. A timeforce diagram such as that illustrated in Fig. 12 is then obtained in which 1 represents the uni-directional, 11 periodic component and 111 the resultant force. From the resultant pulsating force 111, the diagram shown in Fig. 13 may be deduced, which represents a progressive pulsating movement. It will be understood that Fig. 13 only represents the general character or diagram of the path which will depend in form to a large extent on theuseful work done. It gives, however, a good ideaof the kind of movement even in the extreme case of a hammer where the whole work is performed in a single moment, namely by the blow. Fig. 13 illustrates the rising, falling and progressive movement such as that can hihited by a hammer when driving a pile or nail forwards or when shaping or forming the metal to be worked. Fig. 14: is a diagrammatic illustration of the mechanism for producing a progressive oscillatory motion and Fig. 15 i1lustrates a practical example thereof.

Owing to the action of the spring X and the reciprocating weight W, a pulsating force acts upon the body V thus producing the progressive movement at the same time as the oscillation. In practice only the progressive component is of use, the oscillatory movement being an auxiliary movement which only indirectly assists or creates the progressive movement. This is clear from Fig. 15 which illustrates a pile driver where naturally the progression only of the pile is of importance, the pile constituting a;

unit with the driving tup V when the blow takes place. The spring X acts upon the tup V and is adjustable vertically by means of a hand wheel Z The lower spring U is entirely inoperative when the pile driver is in complete operation, owing to the fact that the distance a is greater than the height of the blow Z The spring U serves when necessary to limit or mitigate the blow for which purpose it may be vertically adjusted by means of a hand wheel 2 The form of the reciprocating weight W here selected is that illustrated inFigs. 6 and 7 It is driven by the square shaft 0 which in turn is rotated by a spiral spring Y. The spring is wound up by the motor D, the object of this driving arrangement being hereinafter described.

\Vhen the tup rises, the tension on the spring X is increased and during the down stroke thetup V is not only thereby accel erated but also by the spring X so that it rebounds against the weight WV. Both cooperate in such a manner, at the moment when the blow takes place, that the work in a progressive sense, that is, the velocity of the tup during the blow and thus the strength of the blow practically attains a maximum.

If the spring X is dispensed with, only the force of gravity acts 0-11 the tup V as a constant uni-directional force. There thus exists a peculiar case where no actual mechanical means limits the sphere of action of the reaction driving gear, thus in reality forming an example of continuous displacement of the centre of oscillation iereinbefore referred to.

The reaction driving gear has the characteristic that the turning moment on the driving shaft varies considerably throughout one revolution. It differs according to whether the reciprocating weight W is being retarded or accelerated. That this must be the case will be readily apparent from Fig. 2. Now if, as with a hammer, two successive amplitudes vary considerably, as in the case of the rise and fall of a hammer, or should there be a sudden dissipation of the energy as at the moment when the blow takes place, the maximum turning moment will become so great during one cycle that constructional parts such as shafts, toothed wheels, etc., are exposed to danger. It is therefore dosirable in conjunction with the reaction driving gear to employ a driving means which will not permit the occurrence of high turning moments, but which will in angular velocity to such an extent that the exceptionally high maximum is avoided. The sp 'ing Y in Fig. 15 represents such a driving means which is interposed between the motor D and the shaft O. The spring Y, instead of beingicontinuously wound up by the electro motor D may also be periodically wound up by any other suitable means. The spring driving means then constitutes a unit of the construction of the reaction driving gear and an important element thereof. In the case of a hammer the spring so acts that towards the end of the down stroke, the maximum angular velocity is attained and the blow is thus increased. The tup receives at the last moment a particularly strong impulse.

ln the construction illustrated in Figs. 6

and 7 the masses are'located in part in the e-Xce'ntrics therein used. The location Within the exeentrics of the masses required for the reactionmay be carried to such an extent that the body no longer appears as such. Claims 1. Reciprocatory mechanism comprising a slidable, reciprocatory, revoluble driving member an inertia element adapted to be reciprocated by saidrevoluble member and crank mechanism whereby the inertia of the inertia element reacts with the revolub'le driving member to reciprocate said member, means being provided for utilizing the motion developed fordoing external Work.

2. In combination with reciprocatory mechanism as specified in claim 1, means for controlling the limits of travel of the reciprocatory member and consequent limits of travel of theinertia element.

3. Reciprocatory mechanism as specified 1n claim 1 1n wh ch progressive reciprocation step-by-step 111 one direction is obtained by means of unidirectional displacement of an inner eccentricand a freely movable journal for said inner eccentric.

5, Reciprocatory mechanism comprising a driving shaft, a plurality of oppositely rotating inner eccentrics driven from said shaft, a plurality of outer eccentrics mounted on said inner eccentrics and a freely movable journal for said inner eccentrics.

6; Reciprocatory mechanism as specified in claim 5 having a Weighted element supported by the outer excentrics.

RUDOLF GOLDSCHMIDT- 

